Information: Memorial Sloan Kettering Cancer
Center, the oldest and largest private
cancer center, located in New York, founded in 1884.
Scientific Name: Coriolus versicolor,
Trametes versicolor, Polyporus versicolor, Polystictus
Common Name: PSK, PSP, VPS, Turkey
Tail, Yun Zhi, Kawaratake, Krestin
Brand Name: Krestin
Bottom Line: Coriolus versicolor extracts
have been studied in cancer patients with some positive
results. However, more studies are needed to verify their
Coriolus versicolor is a mushroom that is used in
traditional Chinese medicine as a tonic. PSK and PSP,
polysaccharide compounds isolated from Coriolus, were shown
to improve immune function in patients with certain cancers
when used along with chemotherapy.
- To prevent and treat cancer
When used in combination with certain chemotherapy
regimens, PSK has been shown to benefit patients following
surgical removal of stomach and colorectal cancers.
Clinical trials in patients with breast cancer, leukemias,
and liver cancer do not show beneficial results.
- To reduce the side effects of chemotherapy
Animal studies suggest that PSK can prevent
chemotherapy-induced immune suppression, but clinical
trials have not been performed to confirm this effect in
- To stimulate the immune system
Studies in animals and human volunteers suggest that PSK
might stimulate the immune system.
- To treat infections
Coriolus' effects against infections have not been studied
in the laboratory or in clinical trials.
- To reduce the side effects of radiation therapy
Studies in mice and rats suggest that PSK can prevent
radiation therapy-induced immune suppression, but this is
yet to be proven in clinical trials.
- Passage of dark colored stools
- Darkening of fingernails
- Low-grade toxicities have been reported when used along
with chemotherapy agents. However, such effects may be
caused by the chemotherapy agents themselves.
PSK is approved for clinical use in Japan. Purified PSK,
PSP extracts, or raw Coriolus extract alone or in
combination with other herbs were used in clinical studies.
However, the clinical effects of these products have not
Coriolus versicolor is a mushroom of the
Basidiomycetes class. It is used in traditional Chinese
medicine as a tonic, and recent studies suggest that it has
immunostimulant and anti-tumor properties. Polysaccharide-K
(PSK), a proprietary product derived from Coriolus, was
developed for cancer treatment in Japan. When used as an
adjuvant, PSK appears to improve survival rates in patients
with gastric (1)
(4) (5) cancers. Other Coriolus
extracts, such as polysaccharide-peptide (PSP) and VPS, are
available as dietary supplements. One clinical study
demonstrated that when used in conjunction with
chemotherapy, PSP may benefit patients with advanced
non-small cell lung cancer (6).
Other clinical studies using Coriolus extract alone or in
combination with other botanicals also suggest positive
immunomodulatory effects (7)
However, studies on breast cancer (9),
hepatocellular carcinoma (10),
and leukemia (11)
produced mixed results. A hot water extract of Coriolus,
VPS, was found to enhance development of large intestinal
tumors in mice (12).
Coriolus extracts are generally well tolerated but minor
adverse effects have been reported.
Many over-the-counter Coriolus products are not
standardized, making it difficult to compare potency between
brands. It is also unclear if PSK, PSP, and other Coriolus
extracts have comparable effects.
- Cancer prevention
- Cancer treatment
- Chemotherapy side effects
- Radiation therapy side effects
- Strength and stamina
Proteoglycans: Polysaccharide-K (PSK), a
beta-1,4-glucan (isolated from the CM-101 strain),
polysaccharide-P (PSP), isolated from the COV-1 strain.
Coriolus versicolor is thought to be a biological response
modifier. PSK has been found to induce cytokine expression
in human peripheral blood mononuclear cells in vitro. In
other studies, PSP, as well as Coriolus extract, selectively
induced apoptosis of human promyelocytic leukemia HL-60
also increased apoptotic cell death in cells that had been
treated with camptothecin. In these cells, PSP reduced
cellular proliferation, inhibited cell progression through
both the S and G2 phases of DNA replication, reduced 3H -
thymidine uptake, and prolonged DNA synthesis time (14). An additional in vitro
study showed that a medicinal mushroom blend that included
Coriolus inhibited cell proliferation and induced cell cycle
arrest at the G2/M phase in the invasive human breast cancer
cell line MDA-MB-231 (15).
DNA-microarray analysis indicated that the mushroom extract
inhibited the expression of cell cycle regulatory genes and
suppressed metastatic behavior through the inhibition of
cell adhesion, cell migration, and cell invasion. The
inhibition of metastatic behavior was linked to the
suppression of urokinase plasminogen activator (uPA) (15). PSP has also been shown
to inhibit the interaction between HIV-1 gp120 and CD4
receptor, HIV-1 transcriptase activity, and glycohydrolase
enzyme activity associated with viral glycosylation (16).
Several animal studies report of synergism between PSK and
biologic therapies, including a concanavalin A-bound L1210
vaccine and the IgG2a monoclonal antibody against human
colon cancer cells (17).
PSP induces cytokine production and T-cell proliferation,
and prevents immune suppression due to cyclophosphamide in
animal models. Peritoneal macrophages isolated from mice
that were fed PSP show increased production of reactive
nitrogen intermediates, superoxide anions, and tumor
necrosis factor (18).
PSP also shows analgesic activity in mouse models (19).
Non-small cell lung cancer patients have increased
leukocyte and neutrophil counts, and increased serum IgG and
IgM after consumption of PSP (6).
Healthy volunteers as well as breast cancer patients who
used a formula containing Coriolus and Salvia were found to
have elevated counts of T-helper lymphocytes (CD4+), a high
ratio of CD4+/CD8+, and elevated absolute counts of
TNF-alpha and IL-8 gene expression were also found to be
significantly induced after PSK administration in healthy
volunteers and gastric cancer patients, although individual
response varied (20).
PSK was shown to induce apoptosis in promyelomonocytic
leukemia HL-60 cells without inducing differentiation, and
p38 MAPK (mitogen-activated protein kinas) was found to play
an important role in this process (24).
Animal studies with radiolabeled PSK show that it is
partially decomposed to small molecular products in the
digestive tract. The full molecular spectrum of labeled PSK
is absorbed within 24 h following oral administration in
mice. Peak plasma levels of low molecular weight substances
occur at 0.5-1 h in rats and 1-2 h in rabbits, while
molecules the size of PSK appear in serum after 4, 10, and
Radiolabeled PSK or its metabolites were detected in the
digestive tract, bone marrow, salivary glands, thymus,
adrenal gland, brain, liver, spleen, pancreas, and tumor
tissue in sarcoma-bearing mice. Activity remained high
longest in the liver and bone marrow.
Approximately 70% of radiolabeled PSK is excreted in expired
air, 20% in feces, 10% in urine, and 0.8% in bile.
Approximately 86% is excreted within 24 h.
Adverse reactions from Coriolus are rare. But passage of
dark colored stools (not originating from occult blood) (21),
darkening of fingernails (22),
and low-grade hematological and gastrointestinal toxicities
have been reported when used in conjunction with
chemotherapy agents (3).
However, such effects may be caused by the chemotherapy